Numerous suspension systems have been designed to attach an axle to a vehicle. Many vehicles employ suspension systems utilizing longitudinally extending trailing beams or rocker beams, also known as control arms. These beams are typically pivotally connected to the vehicle chassis or frame undercarriage at a first end, and attached to a transversely mounted axle at or near a second end. For each axle, one beam is generally located near each of the left and right sides of the vehicle. Often, a suspension member, such as an air spring, leaf spring or coil spring, is positioned between the vehicle chassis and the axle mounting end of the suspension beam. In this configuration, when the vehicle axle encounters a rough surface and is displaced by movement of the tires attached thereto, the suspension member can manage the magnitude and speed of the displacement of the control arm while such beam pivots about the first end pivot connection.
Current trends in axle manufacturing, particularly for large trucks and trailers, are to integrate the axle and suspension system. Generally, unitized systems include axles which are permanently fixed within an end of a suspension control arm and have a resilient pivotal bush at an opposing end of the control arm. The bush, often made from a hyperelastic material, is subject to periodic replacement due to wear and aging. However, unitized systems make bush replacement difficult, and often lead to premature replacement of the entire system when only bush replacement was necessary. Thus, it is desired to have a suspension system providing ease in bush replacement without necessitating the replacement of the whole system, and without requiring the use of specialized tools or equipment. Further, such a system would desirably provide a cost and weight savings over current designs.